N-Phenyl-N-purin-6-yl ureas: The design and synthesis of p38α MAP kinase inhibitors

The design, synthesis and SAR of a series of 2,6,9-trisubstituted purine inhibitors of p38α kinase is reported. Synthetic routes were devised to allow for array synthesis in which all three points of diversity could be facilely explored. The binding of this novel series to p38α kinase, which was predicted to have several key interactions in common with SB-203580, was confirmed by X-ray crystallography of 19 (p38 IC50=82 nM).